Originally published in The Proceedings of The International Maple Symposium, 2002. The Maple Society Open Science Initiative presents the first ever digital edition of this important and frequently referenced paper, which updated the the Acer classification presented by de Jong in Maples of the World in 1996, and remains pertinent today.

Recovering the paper required using high definition scans and optical character recognition (OCR). Images were extracted and rebalanced, parts of the tables and references had to be retyped, and the paper was then laid out in the spirit of the original. Special thanks to Piet de Jong for giving me one of his two copies of the Proceedings, and so allowing us to bring the paper to the attention of those botanists who have seen it referenced but been unable to read it.